docs: def _write_apt_gpg_keyfile(key_name, key_material):
      """Writes GPG key material into a file at a provided path.
  
      :param key_name: A key name to use for a key file (could be a fingerprint)
      :type key_name: str
      :param key_material: A GPG key material (binary)
      :type key_material: (str, bytes)
      """
      with open('/etc/apt/trusted.gpg.d/{}.gpg'.format(key_name),
                'wb') as keyf:
          keyf.write(key_material)